Performance evaluation of patent assignee on microalgae biofuels by h-index and h-type indices

The combination of energy storage technology and renewable energy generation technology can make energy storage and renewable energy become a joint system, enhance the flexibility and controllability of power system, and is an important means to realize the industrialization of renewable energy. As one of the primordial plants with the highest photosynthetic efficiency, microalgae show the faster growth rate and higher oil production efficiency than the biofuel made from animals and plants, which have attracted worldwide attention as the renewable and environmentally friendly energy material with great development potential. A comparison is made among the top 23 patentees in the total number of microalgae biofuel patents from 2000 to 2019 (Data Source: Derwent Innovations Index) by using h-index and h-type indices. The research results show that the number of patent applications for microalgae biofuel technology reached a peak in 2011, and then showed a declining trend year by year. Some patentees in the United States, China and South Korea perform well in terms of the quantity of patents, while China and South Korea are far behind the United States in terms of the technological strength shown by h-index, g-index and P-index. The h-index and its derivative indexes are effective in patentee performance evaluation, but p-index is more effective in patentee performance evaluation.